Field of the Invention
The present invention relates to a magnetorheological (MR) damper, and more particularly, to an MR damper, in which since a bypass space that is not affected by an electromagnetic field is secured by forming a cutaway groove penetrating in a direction of compression and rebound strokes at a side surface of a magnetic core, the cutaway groove is formed corresponding to both directions, so that it is unnecessary to match a direction of a passage to thereby achieve ease of assembling, and it is unnecessary to form a bypass holes in an upper plate and a lower plate to thereby reduce processing costs.
Description of the Related Art
In general, a magnetorheological (MR) damper refers to a device that generates an electromagnetic field due to an electric current applied from the outside and changes a damping force through a change in a viscosity of an MR fluid.
The MR damper includes a cylinder which is filled with an MR fluid (magnetic fluid), a piston rod which reciprocates within the cylinder, a piston which is connected to the piston rod, and an electromagnetic field generator which generates an electromagnetic field.
The piston includes a magnetic core which forms a bypass passage and around which a coil is wound, a flux ring which is connected in a state of surrounding the outside of the magnetic core and forms a main passage, and plates which are respectively connected to the upper and lower sides of the flux ring and the magnetic core and form passages to communicate with the bypass passage.
In the MR damper, the MR fluid passes through the main passage during compression and rebound strokes of the piston rod. At this time, the MR fluid is not affected by resistance in a state in which the electric current is being applied from the outside.
On the other hand, in a state in which the electric current is being applied, an electromagnetic field is formed over the outer peripheries of a solenoid, the piston, and the cylinder. This increases the viscosity of the MR fluid existing within the passage. At this time, the piston generates a high damping force while sliding along the high-viscosity fluid.
However, in an existing MR damper, a passage communicating with a bypass hole needs to be formed in the plate. Thus, it costs much to form the passage, and the direction of the passage formed in the plate needs to be matched, making assembling difficult.
In addition, in the existing MR damper, the bypass hole is formed adjacent to the central axes of the magnetic core and the plate. Thus, it is difficult to ensure a space for installing an anti-collision stop rubber.
As the prior art document related to the present invention, Korean Patent Application Laid-Open No. 10-2012-0129580 (Nov. 28, 2012) discloses an MR damper.